Emissions data (model.emissions)

model.emissions contains codes for working with emissions data, including policies on emissions.

In general, models created with message_ix_models:

  • Use tonnes of carbon equivalent (“t C”) as units for mass of emissions.

  • Use “USD / t C” as units for price of emissions. Because (as of 2022-07-20) iam_units treats “USD” as an alias for “USD_2005”, this is implicitly USD_2005 / t C.

message_ix_models.model.emissions.add_tax_emission(scen: Scenario, price: float, conversion_factor: float | None = None, drate_parameter='drate') None[source]

Add a global CO₂ price to scen.

A carbon price is implemented on node=“World” by populating the MESSAGEix parameter tax_emission, starting from the first model year and covering the entire model horizon. The tax has an annual growth rate equal to the discount rate.

The other dimensions of tax_emission are filled with type_emission=“TCE” and type_tec=“all”.

  • scen (message_ix.Scenario) –

  • price (float) – Price in the first model year, in USD / tonne CO₂.

  • conversion_factor (float, optional) – Factor for converting price into the model’s internal emissions units, currently USD / tonne carbon. Optional: a default value is retrieved from iam_units.

  • drate_parameter (str; one of "drate" or "interestrate") – Name of the parameter to use for the growth rate of the carbon price.